[U-Boot-Users] need PPC asm. help. for 83xx watchdog

[U-Boot-Users] need PPC asm. help. for 83xx watchdog

[David Updegraff]

Hi.

Attempting to enable&use watchdog in 8343; but run into Assembler
(v.2.15) problem in cpu/mpc83xx/start.S:424
....
/* and reset it */
	li	r4, 0x556C
	sth	r4, SWSRR at l(r3)
	li	r4, 0xAA39    <-------- gas barks here, 0xAA39 > 0x8000
	sth	r4, SWSRR at l(r3)

which I do not understand, since I thought 'li' was an UNsigned 16bit
load. I can work around it in a kludgey way with.

	lis	r4, 0
	ori	r4, r4, 0xAA39
	sth	r4, SWSRR at l(r3)

but wonder if one you PowerPC assembler gurus could offer better suggestion.

Thanx.

-dbu.

[U-Boot-Users] need PPC asm. help. for 83xx watchdog

[Jerry Van Baren]

David Updegraff wrote:
> Hi.
> 
> Attempting to enable&use watchdog in 8343; but run into Assembler
> (v.2.15) problem in cpu/mpc83xx/start.S:424
> ....
> /* and reset it */
> 	li	r4, 0x556C
> 	sth	r4, SWSRR at l(r3)
> 	li	r4, 0xAA39    <-------- gas barks here, 0xAA39 > 0x8000
> 	sth	r4, SWSRR at l(r3)
> 
> which I do not understand, since I thought 'li' was an UNsigned 16bit
> load. I can work around it in a kludgey way with.
> 
> 	lis	r4, 0
> 	ori	r4, r4, 0xAA39
> 	sth	r4, SWSRR at l(r3)
> 
> but wonder if one you PowerPC assembler gurus could offer better suggestion.
> 
> Thanx.
> 
> -dbu.

"li" is a simplified mnemonic which is actually "addi" (which 
sign-extends the immediate value) according to  the "PowerPC 
Microprocessor Family: The Programming Environments" Appendix F (p. F-15).

Why gas barks, I'm not quite sure.  Probably because it suspects you 
wanted it unsigned (which actually is the case - I hate it when tools 
are smarter than me).

gvb

[U-Boot-Users] need PPC asm. help. for 83xx watchdog

[Pantelis Antoniou]

On Friday 06 January 2006 17:36, Jerry Van Baren wrote:
> David Updegraff wrote:
> > Hi.
> > 
> > Attempting to enable&use watchdog in 8343; but run into Assembler
> > (v.2.15) problem in cpu/mpc83xx/start.S:424
> > ....
> > /* and reset it */
> > 	li	r4, 0x556C
> > 	sth	r4, SWSRR at l(r3)
> > 	li	r4, 0xAA39    <-------- gas barks here, 0xAA39 > 0x8000
> > 	sth	r4, SWSRR at l(r3)
> > 
> > which I do not understand, since I thought 'li' was an UNsigned 16bit
> > load. I can work around it in a kludgey way with.
> > 
> > 	lis	r4, 0
> > 	ori	r4, r4, 0xAA39
> > 	sth	r4, SWSRR at l(r3)
> > 
> > but wonder if one you PowerPC assembler gurus could offer better suggestion.
> > 
> > Thanx.
> > 
> > -dbu.
> 
> "li" is a simplified mnemonic which is actually "addi" (which 
> sign-extends the immediate value) according to  the "PowerPC 
> Microprocessor Family: The Programming Environments" Appendix F (p. F-15).
> 
> Why gas barks, I'm not quite sure.  Probably because it suspects you 
> wanted it unsigned (which actually is the case - I hate it when tools 
> are smarter than me).
> 
> gvb
> 
> 
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Did you tried using li r4, 0xaa39 at l ?

Pantelis